40 degrees is fine, foolish. Prolonged temps under 32 can start to cause damage. Limes are the least cold tolerant. Mandarins, on the whole, the most cold tolerant.

Patty S.

I have most of mine in an unheated detached garage. I usually keep them towards the front of the garage so I can pull them outside on sunny days and push them back in at night. I have a tangelo in this group and it is actually doing very well (may be getting ready to bloom). I am keeping what is left of my lime inside at night and trying to get it lots of sun during days to help it overcome root rot.

My Armstrong Satsuma has done well for two winters outside with just some basic protection other than this week

Hi Patty,
About how long is considered 'prolonged temps'? I have a small in ground Mandarin. We drop to 32* quite often.

JoJo

Well, if you've got a Satsuma mandarin (most common satsuma cultivar is the Owari), JoJo, you're probably just fine. Satsumas can withstand prolonged (longer than 3 hours) temps in the 20's just fine. And, can withstand drops to the teens. 32 degrees would not bother a Satsuma at all. Or a Gold Nugget mandarin for that matter.

Patty S.

I don't have either of the ones you mentioned Patty. Figures. lol...

My in ground is . W. Murcott , rootstock c-35

And my new one is Clementine (Algerian) same rootstock. It has a tag that says hardy to 20*.

I don't always think to cover the in ground, so was curious as to how much it can take,.

JoJo

They'll both be fine, JoJo. The worst you might see is if you had any late, tender flush that might get a bit nipped. Being on trifoliate rootstock also helps to impart some additional cold tolerance. Both can take temps down in the 20's, with your W. Murcott possibly being a bit more sensitive, but it is mostly mandarin (with a small percentage of orange in its background), with the Clementine being all mandarin and pretty darned hardy. If you get worried at all, and know you're going to have a serious cold snap, just string some mini-Christmas tree lights (the older kind, not the LED kind), and then cover it with frost cloth. If you can put up stakes to drape the frost cloth over, so it doesn't touch the leaves, and then make sure the cloth goes all the way down to the ground and can be secured either with rocks, blocks or dirt so that it is air tight, that will help. You can also place a large bucket of water under the frost cloth, or, flood the ground under the tree with water before you put up lights and covers. But, that would be temps in the low 20's with wind. Otherwise, it will do okay for you!

Patty S.

Link lists citrus sensitivity order. I have found young trees (2 yrs. in ground) more sensitive than older trees with a canopy. Mixed hybrid trees often confer a bit of protection if one parent is hardier that another. Cocktail "grapefruit," Oroblanco (weird since pumellos are supposed to be more sensitive than grapefruit) "grapefruit," and as noted Bearss lime (aka Tahitian, Persian) and Meyer and Improved Meyer Lemon. Be sure you know how to use frost cloth.

Here is a link that might be useful: Growing Citrus